Field of the Invention
This invention relates to a device for use in the initiation of a linear pyrotechnic or explosive means such as detonating cord and, more particularly, to a device for coupling a detonating cap to detonating cord.
In mining and other blasting operations, it is often necessary to join two linear members in signal transmission relationship, such as one detonation signal transmission line to another, or to a linear pyrotechnic or explosive member, so that a detonation signal may pass from one to the other. One of such linear devices may be, e.g., a signal transmission line such as shock tube, which generally comprises a hollow tube which has a coating of a reactive material, e.g., pulverulent PETN or a mixture of powdered aluminum and a pulverulent explosive, on its interior wall. See, e.g., U.S. Pat. No. 3,590,739 to Persson, dated Jul. 6, 1971 and U.S. Pat. No. 4,607,573 to Thureson et al dated Aug. 26, 1986. It is often necessary to amplify a signal by use of a detonator cap in order to initiate another device or signal transmission line. Accordingly, a signal transmission line such as a shock tube may be connected at one end with a detonator cap which is detonated by the ignition signal transmitted through the shock tube and which releases, upon detonation, energy sufficient to detonate another device to which the initiation signal is thus transferred. The prior art reflects a knowledge of a variety of coupling devices by which the detonator cap is disposed in signal transmission relation to a target device.
U.S. Pat. No. 3,129,663 to Schnepfe, Jr., dated Apr. 21, 1964 discloses a fitting for low energy detonating cord. The fitting or coupling 10 joins two lengths of low energy detonating cord (LEDC) each of which has a booster cup 21 crimped at their respective ends. The coupling 10 has a longitudinal bore therethrough dimensioned and configured to receive the ends of the respective LEDC lines such that the booster cups are adjacent to one another within the coupling. Further, each LEDC has a ferrule crimped thereto providing a flange, e.g., 24, which bears against the end 27 of the coupling. The LEDC passes through a threaded connector cap 38 which cooperates with corresponding threads at the ends 27 of coupling 10, to clamp flange 24 therebetween when cap 38 is secured onto end 27. Coupling 10 is also provided with relief vents 41 that are protected by bushings 43. The ends of both LEDC lines must be equipped with the crimped ferrules in order for the coupling to function.
U.S. Pat. No. 3,460,477 to Heidemann et al, dated Aug. 12, 1969 discloses a one-way detonation transfer device that features opposing threaded wells for receiving the ends of detonating cords having threaded fixtures secured thereto.